What are "L" and "Y" codes for a 350??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

92470 · 04-10-2007, 10:01 PM

I am trying to replace the choke thermostat on my 71' Cheyenne and am having a heck of a time with finding the right one. The one it has in it now it stamped with a "232-3" on the top of the spring, but I can't reference that anywhere.

I've narrowed it down to 2 possible units. One calls out a number for a 5.7L with a "Y" or "L" engine code, and the other for just a 5.7L. My truck has the stock 350 with the stock 4bbl Quadrajet all original to the truck. I can't find one in the parts stores, and the ones I see on eBay for a 350 4bbl seem to exclude a 1971 truck.

Can anyone please clue me in on the "L" and "Y" codes? I think this will solve my problem.

Thanks in advance.

brak · 04-10-2007, 10:12 PM

Those typically refer to your VIN. and won't help if your motor has been replaced someplace down the line.

92470 · 04-10-2007, 10:24 PM

Both the motor and carb are original to the truck. My VIN doesn't have a "L" or a "Y" in it, so I'm guessing those codes don't apply to my application?

The only letters my VIN has in it are C, E, and S.

Bus Ted Knuckle · 04-10-2007, 10:44 PM

I might not be reading something right but if you have a 350 in your 71 truck you have a choice of three engine codes: E, A, and B

E = 2 Barrel 350 CID V8

A = 4 Barrel 350 CID V8

B = 4 Barrel 350 CID V8

google advance auto's web site, and fill in the info for your 71. It should spit out the right parts unless something has been changed over the years.

Edit by me:

I see from your later post that you list the letters in your VIN as C, E, and S. E is your engine code. That means that supposedly your truck came original with a 350 2 barrel. Not very many (if any) did have 2 barrel from the factory, but advance lists your choke thermo as:

http://www.partsamerica.com/productd...pe=274&PTSet=A

Now, that is for a 2 barrel carb!!!

You are saying that you now have a 4 hole...so there is no telling what someone has put on there in 40 years

brak · 04-10-2007, 11:12 PM

A pic would be very helpful...

92470 · 04-11-2007, 08:33 PM

I know the engine and carb are original for sure, because I bought it from the original owner that is a family friend. The thing that is confusing about the engine code meanings everyone has given me is that they don't make sense according to what General Motors published in their service manuals.

According to GM, the "C" in my VIN stood for "Conventional Cab, the "E" stood for "V-8 Gasoline" and the "S" stood for "St. Louis manufacturing plant". The factory service manual explains the whole VIN combination. The type of carb doesn't seem to be referenced of of any of them

I did find the right choke thermostat after comparing it to pictures on eBay, so no more problem.

Thanks for all the comments and suggestions!

04-10-2007, 10:01 PM	#1
92470 Registered User Join Date: Nov 2006 Location: Maple Grove, MN Posts: 149	What are "L" and "Y" codes for a 350??? I am trying to replace the choke thermostat on my 71' Cheyenne and am having a heck of a time with finding the right one. The one it has in it now it stamped with a "232-3" on the top of the spring, but I can't reference that anywhere. I've narrowed it down to 2 possible units. One calls out a number for a 5.7L with a "Y" or "L" engine code, and the other for just a 5.7L. My truck has the stock 350 with the stock 4bbl Quadrajet all original to the truck. I can't find one in the parts stores, and the ones I see on eBay for a 350 4bbl seem to exclude a 1971 truck. Can anyone please clue me in on the "L" and "Y" codes? I think this will solve my problem. Thanks in advance.

04-10-2007, 10:12 PM	#2
brak Registered User Join Date: Apr 2006 Location: MinneSNOWta Posts: 1,381	Re: What are "L" and "Y" codes for a 350??? Those typically refer to your VIN. and won't help if your motor has been replaced someplace down the line. __________________ 2003 GMC Sierra 1500 WT 1995 Nissan Hardbody 2016 Hyundai Veloster Turbo DC2 (SW/AW) Clyde W. Harvey USN "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery" Winston Churchill Last edited by brak; 04-10-2007 at 11:11 PM.

04-10-2007, 10:24 PM	#3
92470 Registered User Join Date: Nov 2006 Location: Maple Grove, MN Posts: 149	Re: What are "L" and "Y" codes for a 350??? Both the motor and carb are original to the truck. My VIN doesn't have a "L" or a "Y" in it, so I'm guessing those codes don't apply to my application? The only letters my VIN has in it are C, E, and S.

04-10-2007, 10:44 PM	#4
Bus Ted Knuckle Son of a gun Join Date: Jan 2007 Location: Hot Springs, Arkansas Posts: 1,636	Re: What are "L" and "Y" codes for a 350??? I might not be reading something right but if you have a 350 in your 71 truck you have a choice of three engine codes: E, A, and B E = 2 Barrel 350 CID V8 A = 4 Barrel 350 CID V8 B = 4 Barrel 350 CID V8 google advance auto's web site, and fill in the info for your 71. It should spit out the right parts unless something has been changed over the years. Edit by me: I see from your later post that you list the letters in your VIN as C, E, and S. E is your engine code. That means that supposedly your truck came original with a 350 2 barrel. Not very many (if any) did have 2 barrel from the factory, but advance lists your choke thermo as: http://www.partsamerica.com/productd...pe=274&PTSet=A Now, that is for a 2 barrel carb!!! You are saying that you now have a 4 hole...so there is no telling what someone has put on there in 40 years __________________ Bill BEATERS ARE NEATER Last edited by Bus Ted Knuckle; 04-10-2007 at 11:16 PM.

04-10-2007, 11:12 PM	#5
brak Registered User Join Date: Apr 2006 Location: MinneSNOWta Posts: 1,381	Re: What are "L" and "Y" codes for a 350??? A pic would be very helpful... __________________ 2003 GMC Sierra 1500 WT 1995 Nissan Hardbody 2016 Hyundai Veloster Turbo DC2 (SW/AW) Clyde W. Harvey USN "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery" Winston Churchill

04-11-2007, 08:33 PM	#6
92470 Registered User Join Date: Nov 2006 Location: Maple Grove, MN Posts: 149	Re: What are "L" and "Y" codes for a 350??? I know the engine and carb are original for sure, because I bought it from the original owner that is a family friend. The thing that is confusing about the engine code meanings everyone has given me is that they don't make sense according to what General Motors published in their service manuals. According to GM, the "C" in my VIN stood for "Conventional Cab, the "E" stood for "V-8 Gasoline" and the "S" stood for "St. Louis manufacturing plant". The factory service manual explains the whole VIN combination. The type of carb doesn't seem to be referenced of of any of them I did find the right choke thermostat after comparing it to pictures on eBay, so no more problem. Thanks for all the comments and suggestions!



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